The invention concerns a coordinate measuring apparatus for measuring three-dimensional or two-dimensional objects in the direction of the X, Y and Z axes of the coordinate measuring device, comprising a measuring table that accommodates the object and can be displaced in the direction of the X axis of the coordinate measuring device, as well as a carriage that can be displaced in the direction of the Y axis of the coordinate measuring device, from which a spindle sleeve extends that can be displaced in the direction of the Z axis of the coordinate measuring system.
The usual embodiments of optical and multisensor coordinate measuring devices are characterized in that the movable axes are arranged distributed between the movement of the measuring object (measuring table) and the movement of the sensors (Z axis). This occurs in order to achieve a sufficiently compact device concept and obtain a guide surface that is as close as possible to the measuring plane that is generally in the interior of the table. As an alternative coordinate measuring devices with movable bridges are also available. In these, only the sensor is moved. A disadvantage that affects this arrangement is, however, that the guide axes have to be arranged at a great distance from the measuring location in the table plane, that is, at the height of the bridge. The guide errors induced by the long lever arms lead to great measuring errors.
The same problems occur when utilizing coordinate measuring devices with an L-shaped construction, since the guideway is arranged in a measuring direction that is far away from the measuring table surface.
The design and assembly of corresponding coordinate measuring devices can be found in German publication entitled Multisensor Coordinate Measuring Technology, Library of Technology, Volume 248, in particular on page 11.
From DE-C-37 33 617 we know of a multiple coordinate measuring machine, in which a measuring table can be displaced on two first guideways along the X axis and a carriage with column can be displaced by two second guideways along the Y axis of the coordinate measuring device. A displaceable carriage extends from the column in the Z direction. The second guideways that guide the carriage run on a separate stand with a lateral offset to the first guideways.
In a coordinate measuring device according to DE-A-41 26 532, bearings are imbedded into a base plate, along which a measured value sensor can be moved in the X and Y directions. The bearings run in different planes. There is also the possibility of mounting a workpiece support on the base plate, which can be supported by air bearings that extend in one plane on one of the bearings of the measured value sensor, but are at a distance therefrom.